package com.github.com.tools;

import java.util.Random;

public class RandomTool {
	
	/**
	 * 获取一定长度的随机数字和字母
	 * @param length 指定字符串长度
	 * @return 一定长度的字符串
	 */
	public static String getStringRandom(int length) {
		String val = "";
		Random random = new Random();
		//参数length，表示生成几位随机数
		for(int i = 0; i < length; i++) {
			String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";
			//输出字母还是数字
			if( "char".equalsIgnoreCase(charOrNum) ) {
				//输出是大写字母还是小写字母
				int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;
				val += (char)(random.nextInt(26) + temp);
			} else if( "num".equalsIgnoreCase(charOrNum) ) {
				val += String.valueOf(random.nextInt(10));
			}
		}
		return val.toUpperCase();
	}
	
	public static void main(String[] args) {
		System.out.println(getStringRandom(5));
		System.out.println(getStringRandom(15));
	}

}
